import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MyPropositions{
	static final char conjunction = '∧';
	static final char disjunction = '∨';
	static final char negation = '¬';
	static final char implication = '→';
	static final char biconditional = '↔';
	public static StringBuilder format(StringBuilder expressionProposition) {
		for(int i=expressionProposition.length()-1; i>=0; i--) {
			switch (expressionProposition.charAt(i)) {
			case '1':
				expressionProposition.setCharAt(i, negation);
				break;
			case '2':
				expressionProposition.setCharAt(i, conjunction);
				break;
			case '3':
				expressionProposition.setCharAt(i, disjunction);
				break;
			case '4':
				expressionProposition.setCharAt(i, implication);
				break;
			case '5':
				expressionProposition.setCharAt(i, biconditional);
				break;
			case ' ':
				expressionProposition.deleteCharAt(i);
			default:
				break;
			}
		}
		return expressionProposition;
	}
	
	
}
/*
¬
∧
∨
⇒
⇔
*/
